1. Field of the Invention
This invention relates to a solid oxide fuel cell that converts chemical potential directly into electric energy, thus generating electric power, and also to a method for manufacturing such a solid oxide fuel cell.
2. Description of the Related Art
It is currently known that single cells of solid oxide fuel cell are constructed of inner electrode, electrolyte and outer electrode on the annular porous substrate tube. A interconnection extends from a predetermined section of the inner electrode for each respective single cell through the associated outer electrode and electrolyte. The inner electrode for a single cell is connected in series with the outer electrode for an adjacent single cell by the interconnection of single cell-via a metallic felt. This prior art is exemplified by Japanese Patent Laid-Open Publication No. 130381/1982.
In putting a solid oxide fuel cell to practical use, it has hitherto been a significant aim to improve the efficiency of generating electric power; various studies have therefore been made to reduce the cell thickness to a minimum. In one of these studies, the thickness of the porous support tube, which serves to supply fuel gas to the electrodes, is reduced in an effort to more efficiently discharge the product of reaction and introduce the fuel gas to the electrodes, both of which are believed to be useful in improving the efficiency of generating electric power.
In the prior solid oxide fuel cell, however, partly since the electrodes, the electrolyte, the interconnections, etc. must be supported on the porous support tube, and partly since one single cell connected therewith in parallel or in series must be supported at the other single cell via a metallic felt, the thickness of the support tube must be thick enough to have a sufficient degree of strength and durability. It is also necessary to connect cells in parallel or in series via the metallic felt. Consequently assembling of the solid oxide fuel cell is difficult to achieve.